Process for refining vegetable and animal oils and fats



Patented July 31, 1934 I I 1 9 8 252,

PROCESS FOR "REFINING VEGETABLE AND ANIMAL OILS AND FATS WilhelmGensecke, Gonzenheim, near Frankforton-the-Main, Germany, assignor toAmerican Lurgi Corporation, New'York, N. Y., a corporation of New YorkNo Drawing. Application January 9, 1933, Serial No. 650,946. In GermanyNovember 25, 1932 1- Claim. (01. iii-12) This invention relates to aprocess for refining The turbid layer containing the mucines andvegetable andanimal oils and fats, and more parother precipitatedimpurities was separated from t cularly to that stage in the refining ofthe said the oil by. drawing off said layer from the vessel o ls or fatswhich is concerned with the separabymeans of an outlet device providedat the lowt on of the impurities-hereinafter termed muestpoint of thevessel. In order to eliminate the cines or phosphatidesin colloidalsolution in the final traces of precipitant (e. g. acid) from the oil,crude oil, and of the fatty acids. the latter had then to be repeatedlywashed with These mucines, phosphatides or the like, 001- hot water.loidally dissolved in the crude oil are separated For the purpose ofneutralization, the oil, freed out during the separation of the freefatty acids from the mucines and the like, was next pumped bysaponification with alkali or other neutralizing into the actualrefining apparatus, where the agents. In that operation the mucinesbecome fatty acid was separated from the oil-by saponifienveloped in theflakes of the fatty-acid soap and cation with alkali. Although theresulting oils greatly increase the bulk of the latter. These wereneutral and entirely free from mucines and 15 voluminous soap flakesonly bed together loosely, like impurities, and a better yield of oilwas obon deposition, and therefore occlude. a good deal tained than bymerely refining with alkali, withof neutral oil. out any specialpre-refining, the quality of the In order to lessen this loss of neutraloil during oils was mostly inferior to those treated 'solely therefining process, certain so-called pre-refining with alkali, that is toSay, Without D fi n 20 processes have been devised with the object ofwith acid or saline electr y I depositing and removing the colloidallydissolved According t t process of the present invenmucines beforeproceeding to saponify the fatty t the refining o Vegetable el'iahimel011$ acids. The known methods of such pre-refining fats is f d y meansof the o fi n p consist in treating the oils or fats with aqueous essknown per with saline electrolyte l s,

2 solutions, for example of organic and inorganic and by neutralizingthe fatty acids with alkali. 30 acids, saline electrolytes, tanningagents and the In C a ever, to the usualmpthod o p like. Thepre-refining by these known methods cedure, the pre-refining andneutralization are was performed in special apparatus, adapted, f d in aSingle l Operation, inasmuch both in respect of material and shape, tothe puras the alkali required for neutralizing first the 30 pose inview, In th first l e, the 011 or fat, t fatty acids and secondly thoseacids still present be treated was energetically stirred, in a 1, onaccount of the pre-treatment with acid-saline with the medium (reagent)intended t precipi-' electrolytes, is added to the oil immediately aftertate the mucines, mechanical stirrersbeing usualthe action of the salineelectrolyte solution or of ly employed, though air was also occasionallyinthe aqueous solution of saline electrolytes and 35 troduced. After theprecipitant had operated for ac d whereby the Various. mucines are D p asufiicient time, the stirrers wereput out of actated. Consequently theprecipitated mucines tion, and the contents of the vessel lefttorestpand the like t he w the uheensumed portion During this stagethe'separated impurities gradof the saline electrolyte solution and thesaline ually settled down to the bottom of the vessel, in solutionderived from the neutralization of the 40 t form of a separate layer ofturbid material excess of acidin cases where an excess of prewhich, whenan acid had been employed as preeipitant. used-remain in the. Oil d thecipitant,'also contained such acid. A source of impurities, e SS 0fprecipitating agent and difiiculty in this treatment was caused by thecir the soap stock formed by the neutralization of cumstance that, onthe one'hand, a considerable t fatty acid a p e p together o the 45 timeis advantageous for obtaining a satisfactory O ldeposition of theimpurities from the oil, whereas, The present invention offers thefollowing adon the other hand, the protracted contact with vantages incontradistinction with the known the precipitantsuch as acid ordissolved saline methods of working. r

electrolyteimpairs the quality of the ,oil. If the The mucinescolloidally dissolved in the crude 50 temperature beraised, in order toaccelerate the oil and other impuritiesare precipitated infloccudeposition of the impurities, thismeasure .also lent form bytheprecipitating agent, namely a has an injurious effect on'thequaiity'of the oil. saline electrolytesolutlon or mixtures of variousThe restriction of this pre-refining to isolated insalineelectrolyte'solutions oracid saline electrostances in practiceisexplained by the aforesaid .lyte solutions. The flakes'thus producedfloat in diffleulty! the oil which is'free from mucine. In this con-.110

nection the acid saline electrolyte solution may either be added as suchto the oil or fat to be treated, or the constituents of the electrolytemixture can be ,added to the oil in succession, that is to say the acidis first added and then the saline electrolyte solution or vice versa.Immediately on precipitation of the colloidally dissolved mucine, alkalisolution or any other suitable neutralizing agent is added to the oil.When employing an acid saline electrolyte solution as the precipitatingagent any excess of acid that may be present is neutralized with theformation of the corresponding salt as is also the free fatty acidpresent. Flakes of soap are formed which include a small quantity onlyof neutral oil. The bodies precipitated out by the saline electrolytesolution or acid saline electrolyte solution, that is to say heavyflakes of mucine and any excess of saline electrolyte solution employedeffect a rapid and eflicient separation of the soap flakes from the oiland when the stirrer is stopped a thick layer of soap and mucine flakesis quickly formed, which includes considerably less neutral oil than thesoap stock which is obtained by known meth-.

Ode of neutralization from crude oil. The soap stock settles downrapidly and an excellent yield of neutral oil free from mucine isobtained having a satisfactory consistency.

The soap stock consisting of soap flakes, entrained neutral oil, salineelectrolyte solution and coagulated mucines and the like, can readily beseparated into high grade neutral oil and high grade fatty acids byextraction with a solvent with subsequent treatment with acids. Byextracting the soap stock with benzene or like oil solvents a solutionof neutral oil-and a mixture of soap and solvent is obtained. The oilsolvent is distilled off from the neutral oil solution leaving theneutral oil. The extracted mixture of soap and oil solvent isdecomposedby inorganic or organic acids into a mixture of fatty acids,solvent and saline solutions, whereupon the solvent autoclave, as isuniversally employed at present and in which the valuable neutral oil isdestroyed, is avoided. The soap stock obtained in the neutralizationprocesses in general employment at the present day contains the mucinesand the like precipitated from the oil in quite a different form fromthat in which these substances. are precipitated according to'theprocess of the present invention. The mucines and the like were thecause of the difliculties which were encountered during the extractionof oil from soap stock recovered by the known processes.

A-single apparatus only is required for the process of the presentinvention, so that the prime and running costs are considerably reduced.In the removal of mucine and neutralization, hitherto usually carriedout separately, there occurs during the separation of the reflned oiland soap stock, approximately twice the loss of oil as in the case ofthe process of thepresent invention, in which only one separation isnecessary of neutral oil and the deposited layer of mucine and soap. Theseparation of mucine may also be efiected at a moderate temperature.

Example 1 1000 Kg. of soya bean oil containing 0.5% of free fatty acidsare heated to 30 C. in an apparatus provided with stirrers. '7 litres ofsaturated magnesium sulphate solution are then added, whilst vigorousstirring is continued. The

vat the bottom of the vessel which contains a small quantity only ofoil. The supernatant. oil is then decanted off. 1

Example 2 1000 Kg. of earth nut oil are warmed'to a temperature of 28 C.in a vessel provided with stirrers. 8 litres of an acid salineelectrolyte solution consisting of 8 volumes of 30% sulphuric acid andfive volumes of saturated sodium sulphate solution are then added withfurther vigorous stirring. The mucines colloidally dissolved in thecrude oil are precipitated in a short time in the form of granularflakes which float in the pure oil. A quantity of caustic soda lye of 18B. is thereupon added with continued stirring suiflcient to neutralize-both the excess mineral acid present in the oil and the free fatty acidalso present. Fine grained soap flakes are formed including a smallquantity of neutral oil. The oil is then warmed to a temperature, of 55C. with further stirring and is thereupon left to stand.

asmall quantity only ofoii. The oil is then decanted.

.I claim: Y

A process for removing mucines, phosphatides and the like and fattyacids from vegetable and animal oils and-fats which comprisesprecipitating the mucines, phosphatidesand the like with salineelectrolyte solutions also containingan acid, and neutralizing the fattyacids and any acid derived from the previous treatment with alkalibefore separating oi! the precipitated impurities, the substancesdeposited during both stages at treatment being separated jointly bysettling from the refined oils 'andfats.

WILHELM GENSECKE.

